Lower Unit Gear Assembly Johnson 115 '69

[tigerone]

Please Help...

I was out on the water this weekend ready to do some fishing. The motor seemed a little bit labored when I would give it gas, but nothing too major. After about 10 minutes runing it....BAM, it quit. It was a rapid quit, really sudden and fast. Tried to start again and saw that the starter was not even turning the fly wheel. Oh !@#* I thought the engine was siezed. No smoke or anything outright hot when I felt it. Took it out of the water and dropped lower unit to separate problem areas. After dropping lower unit the flywheel freed up and turned over great. Not a siezed piston or ring, wheeew. BUT the lower end gear will NOT turn or budge a millimeter. I am into fixing these things and got into the lower unit up to the point where the shaft enters underneath the impellar unit. Took four screws out of square bearing housing and seal assy but cannot get the dang thing off.

Am I barking up the right tree, and if so am I going about getting the gears and rods out correctly.

I am missing a flange on my impellar. Could it be jammed in the gear assy?

Thanks,

Tigerone

 

[Fisherball]

Re: Lower Unit Gear Assembly Johnson 115 '69

Do a search on this site for Johnson motor parts-lower units. There should be an exploded view of all the parts that will show you what's inside & how the parts fit together that may show you what the problem could be.

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

I have the exploded view. Just need to know how to dissasemble the gear assy. Do I start at the BEARING HSG.&SEAL ASSY beneath the impellar unit, or at the BRG. HOUSING SEAL ASSY down by the prop? I have tried to access it through the bearing hsg and seal assy under the impellar unit and cannot get the housing lid off.

Thanks!

Tigerone

 

[Fisherball]

Re: Lower Unit Gear Assembly Johnson 115 '69

On my '81 Johnson 70 hp you start at the bottom by the prop, remove the plate (bearing housing & seal assy) around the prop shaft & prop shaft. Get a long handled rachet to get the bolt on the bottom of the shaft that holds the pinion gear, with another rachet holding the top of that shaft up where it fits into the powerhead. I've never done it but that's what my manual says. That's the shaft you need the shim gauge to put back together. You'll need a long special "C" ring tool, (expensive) & a puller you can make to get the bearing housing out. Definitly worth buying a service manual for. There are lots of little things you have to do to put it back together correctly. You have to replace all the seals in it & lube all the bearings. If you do it right you'll know it'll last a long, long time! The individual parts are very expensive, I think one of the shafts is $325.00 & the gears are 3 digits each if you need to replace them.

 

[Daviet]

Re: Lower Unit Gear Assembly Johnson 115 '69

In order to remove vertical drive shaft you need to remove the pinion nut in the lower unit. Remove the exhaust housing, two large snap rings and reverse gear. That will expose the pinion nut and allow the vertical drive shaft to be pulled out. Some times the vertical shaft bearing housing has to be pried up with a couple of screw drivers.

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

I have now removed snap rings and have accessed the lower unit gear with bottom of vertical shaft and pinion nut showing.

How do I get pinion nut off of vertical shaft? By accessing the nut from the lower unit? The vertical shaft is the one that is binding up and not turning. Is there any way to take off pinion nut without turning vertical shaft with a wrench on pinion nut. A long handled ratchet?

Also what would cause the vertical shaft to seize like that? There is absolutely
no play one way or the other on this thing.

Thanks,

Tigerone

 

[Fisherball]

Re: Lower Unit Gear Assembly Johnson 115 '69

Get a long handled rachet to get the bolt on the bottom of the shaft that holds the pinion gear, with another rachet holding the top of that shaft up where it fits into the powerhead.

You'll have to pull the lower unit from the powerhead. At the top of vertical shaft instead of "another rachet" like I wrote eariler, you'll need a tool designed to fit over the splines on the shaft. There is a bearing housing similar to the one you already pulled at the top of the lower unit, you'll probably have to pull it also. That will give you some play to move the vertical shaft around. I don't think the bottom of the shaft will fit through the bearing housing. If the lower unit is off the power head the vetical shaft should spin, if it doesn't than your problem is in the top bearing housing.

The service manual will really help at this point cuz it tells what needs to be done, without it there is a very good chance some little detail will be missing & you'll trash the lower unit again when it ready to run on the water.

 

[wilde1j]

Re: Lower Unit Gear Assembly Johnson 115 '69

The drive shaft needs to be held using a special tool (or make one by welding a 1/2" drive socket to the bottom end of a scrap crankshaft with the correct number of splines). If you use a pipe wrench or vise grips on the drive shaft, you risk wrecking it. Once you restrain the drive shaft, the pinion nut is removed using an appropriate socket.

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

Got it out. I was able to hook up the wrenches as explained and got pinion nut off. Had to put a lot of back pressure on the bottom of shaft from within the housing to get it to release and back out. Both bearings went south and now I have to get a new bearing housing and new thrust bearing.

I now need to clean off the platform of the Vertical drive shaft where the thrust bearing melted on to it. Any ideas? Had a local machine shop look at it and they said they could put it in a lathe and turn it with a blade to scrape off excess bearing material. Is this a good approach or could I heat it up with torch and scrape it off myself.

Also, if I need a new shaft are there any shafts from other motors that are interchangeable with this one? New shaft is not available for parts (it is way too expesive if it was).

Getting there,

Tigerone

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

Got it out. I was able to hook up the wrenches as explained and got pinion nut off. Had to put a lot of back pressure on the bottom of shaft from within the housing to get it to release and back out. Both bearings went south and now I have to get a new bearing housing and new thrust bearing.

I now need to clean off the platform of the Vertical drive shaft where the thrust bearing melted on to it. Any ideas? Had a local machine shop look at it and they said they could put it in a lathe and turn it with a blade to scrape off excess bearing material. Is this a good approach or could I heat it up with torch and scrape it off myself.

Also, if I need a new shaft are there any shafts from other motors that are interchangeable with this one? New shaft is not available for parts (it is way too expesive if it was).

Getting there,

Tigerone

 

[wilde1j]

Re: Lower Unit Gear Assembly Johnson 115 '69

If you can't clean up the drive shaft , try here for used:

Trixie?s Landing, Bayville, NJ 732-269-5838
American Outboard www.americanoutboard.com
http://www.piratemarinesalvage.com/

TD?s list:
Salvage yards.
sea-way.com
outboard-parts.com
laingsoutboards.com
tcoutboard.com
fairwindsmarina.com
salvagemarine.com
marinepartsoutlet.com
Superior Marine (800-338-9281)

 

[SparkieBoat]

Re: Lower Unit Gear Assembly Johnson 115 '69

sounds like I need those special foot tools also....
Sparkie

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

Got everything cleaned up and new parts in. Do I need to pack the thrust bearing with grease, I am sure I need to. Just good old axle/bearing grease good enough?

 

[wilde1j]

Re: Lower Unit Gear Assembly Johnson 115 '69

All the parts in the lower unit are lubed by the gear oil you fill with after assembly. Never heard of packing any LU parts with any kind of grease.

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

Yes that makes sense. How tight do I torque the pinion nut on bottom of vertical drive shaft?

What type of gear case oil should I use?

Thanks

 

[wilde1j]

Re: Lower Unit Gear Assembly Johnson 115 '69

Shop manual will have the torque value. The shop manual will address proper shimming, which is required for proper pinion/drive gear meshing. Failure to do this step will result in very short life of expensive parts. Gear oil should be marine BRP hi-vis or equal, I think. Any BRP/ERvinrude dealer can verify oil type. You should replace the prop shaft seals, drive shaft seal and shift rod seal while all is apart.

 

[tigerone]

Re: Lower Unit Gear Assembly Johnson 115 '69

Couldn't I just put in the same number and size of shims that were originally in it have it run and function normally?

Thx.

 

[rockyrude]

Re: Lower Unit Gear Assembly Johnson 115 '69

That should be an electric shift lower unit. It uses the premium type c gear lube which is thinner than the normal lube.

 

[wilde1j]

Re: Lower Unit Gear Assembly Johnson 115 '69

Couldn't I just put in the same number and size of shims that were originally in it have it run and function normally?

Thx.

I wouldn't. No guarantee of correct gear meshing if you don't follow the manual.